A Long Time Observation [Color Filters and NVDs]

[JEMelby]

I've been coming to these forums for years. A quick glance to the edge of this text window will reveal that this is my first post. I have been what you would call a "lurker." As such, I can usually find the answers to my questions without actively engaging. For that, I thank you all.

I have some more specific issues that I'd like addressed that will require me to make a post or two, so now I have become an active (as opposed to passive) participant.

I shall do so carefully, tho, as there are a number of you out there with the propensity to CRUSH pretty much anything that is contrary to your own opinion. Also, I don't see alot of Military representation here. The number of posts that I have seen recommending RED filters for deploying soldiers is a bit scary - I bet that a lot of you are soldiers from back in the day. The times have changed - RED = DEAD on the modern battlefield (think night vision devices)

So here I go... looking forward to some quality interaction.

:welcome:

 

[carrot]

Re: A Long Time Observation

Hi there, and welcome to CPF!

I hope to see you around the forums frequently as it seems you have much to contribute.

 

[Zeruel]

Re: A Long Time Observation

:welcome:
Good of you to join in. Need a sensible voice to put those who CRUSH others into place.

 

[american lockpicker]

Re: A Long Time Observation

Hello and welcome to the forum.

 

[Blindasabat]

Re: A Long Time Observation

Welcome! You have already made one valuable contribution, I hope to see you contributing again. Don't be offended by those who take the "I will crush your opinion" approach to posting. They are just opinions like everybody else's. People pay more attention to though out posts with supporting info than the ones that just pose an unsupported opinion. You have already at least alluded to supporting info for your opinion against red filters, but can you give us a little more info on that? Are NV all infra red? Are some UV? Is there an alternative to red in the field?
I'm not in that arena at all, but it's good to know - I'm the kind of person that likes to know a little something about everything... "Just in case."

 

[baterija]

Re: A Long Time Observation

Well I still have uniforms and boots in the closet (thankfully not pressed or polished anymore) and have plenty of experience with vehicle mounted thermal optics and a little with NVG's. I'd be interested in the rationale behind your assertion. Any simple rule of thumb can be exactly the wrong move when applied to a specific situation. Without an understanding of your assertion I can't apply it effectively when assessing light use.

I also know there are many places where deploying US military still come under restrictions from the chain of command where it's red filters or nothing (not that it's the best call but institutional inertia exists). A light you can use beats one you can't use - as long as the user knows how to minimize the risks. Given that a red filter, or separate red emitter still makes sense as a recommendation, even if it's a horrible call for maintaining stealth within line of sight of NVDs.

 

[divine]

Re: A Long Time Observation

Welcome, enjoy your stay.

 

[kramer5150]

Re: A Long Time Observation

Welcome to the forum!!

I think most who recommend red lights, recommend the low lumen variety for night vision preservation.

 

[PetaBread]

Re: A Long Time Observation

:welcome:

 

[Lightraven]

Re: A Long Time Observation

There isn't a whole lot of current military participation on these forums so up-to-date info might be lacking.

Specific tactical information is best left to the individual unit SOP's, not to this message board. People here know what's available, but may not understand how it's used in the field, especially in a specific assignment. SF in Afghanistan reportedly created a new light color SOP based on their experiences there--not related to night vision gear.

 

[FlashCrazy]

Re: A Long Time Observation

:welcome: This should be an interesting thread. I've always wondered if red was really better than other colors (or just white) in regards to low-light applications. There seems to be alot more cyan (green) in use now. I never really liked the way things look when using a red light... I guess it's from my many hours of developing x-ray film years ago under red light. I can't claim to have any real knowledge on the subject, but I'm curious to see future comments here. :candle:

 

[Liquidspaceman]

Re: A Long Time Observation

Welcome to the forum. Good thread topic. Looking forward to comments and your future postins.

 

[Benson]

Re: A Long Time Observation

:welcome: This should be an interesting thread. I've always wondered if red was really better than other colors (or just white) in regards to low-light applications. There seems to be alot more cyan (green) in use now. I never really liked the way things look when using a red light... I guess it's from my many hours of developing x-ray film years ago under red light. I can't claim to have any real knowledge on the subject, but I'm curious to see future comments here. :candle:

The point of red light is to use your color (photopic) vision without using (and killing) your low-level (scotopic) vision. Unfortunately, even photopic response to red is rather low, so it takes a lot of emitted power to get effective red illumination. And then, depending on what red (not just effective or peak wavelength, but also the spectral width), this high power may have enough intersection with the scotopic curve to do some harm to your night-adapted vision anyway.

The other notion, behind cyan or green, is to see the best with a given light output. Your photopic response peaks for green, so green requires the least power to see at a certain level, while cyan is the peak for scotopic vision. But while dim cyan is the most efficient with night-adapted vision, brighter cyan (even the same light, shining on something closer or more reflective) bleaches the rhodopsin and kills your night vision, at which point it's less efficient than green. (Of course, both cyan and green are way brighter than red at the same power, on either response curve...)

I don't really know about the IITs in current NVDs; I guess my assumption had been that they had uniform response across the IR and visual range, but I never explicitly considered it before, and that obviously is not likely the case. Certainly red is one of the worst, simply because of the high power required, but I wonder how sensitive NVDs actually are to 1mW of red vs. 1mW of green -- if their response varies significantly, there could be a different color that's best to maximize the ratio of optical visibility (whether scotopic or photopic) over visibility with NVG. :thinking:

Really, we need a continuously-tunable laser (or array of lasers) with dual cameras, an optically-embedded sensor to determine current rhodopsin levels and compute the optimal wavelength and wattage for given conditions, and maybe even add a high-resolution liquid-crystal mask to allow bright illumination of distant objects without over-illuminating near objects...

 

[rockz4532]

Re: A Long Time Observation

:welcome:

 

[Culhain]

Re: A Long Time Observation

Great first post.

I've heard from returning soldiers that the BGs have learned to fire at red lights, hence red = dead. Please elaborate on NVD devices and current tactics.

 

[Lightraven]

Re: A Long Time Observation

If the original poster and others in the field don't mind, let's limit our discussion of night vision technology and tactics to those with need to know. No point helping our enemies.

 

[Search]

Re: A Long Time Observation

I was under the impression incandescent lights with an IR filter (being as incandescent bulbs product IR light) or IR LEDs are the only thing capable of being used with NVGs and..

..Red and Green color LEDs only preserve night vision.

I can see where the color red + any light would be something to shoot at when it's dark, however.

When using an IR LED or IR filter on an incandescent no one is capable of seeing these with the naked eye.

If we went to war with anyone with NVG technology I would imagine American soldiers would lose this advantage and would also have to stop using the IR beacons/pointers (hence, the ones on the rifles).

This accurate?

 

[Benson]

Re: A Long Time Observation

If the original poster and others in the field don't mind, let's limit our discussion of night vision technology and tactics to those with need to know. No point helping our enemies.

Civilians aren't enemies, and in all probability the actual enemies put more effort towards getting information about technology and viable tactics from actual experimentation, serious research, or direct observation (for current enemies in combat zones, rather than potential enemies) than reading what someone claimed on an internet forum, and trying to guess from the twenty-five opinions (all presented as fact), which ones bear any weight, and which ones are armchair commandos.

I agree that a discussion of which tactics are actually in use, and of some tech, should be offlimits in many cases, but that doesn't mean that discussion of the entire topic should simply be shut down.

 

[Lightraven]

Re: A Long Time Observation

I've discussed NV tech in numerous posts, but there are questions I won't answer and topics I won't discuss--specific tactics, tech weaknesses and limitations, countertactics, specific tech capabilities, etc.

There are a few CPF'ers qualified to discuss these matters, and I don't think it is hard to guess who they are. It's just tempting to correct mistakes, myths or misperceptions and get drawn into a detailed discussion of NV tech and tactics that most of the world doesn't "need to know."

 

[Liquidspaceman]

Re: A Long Time Observation

In other words:

"Loose lips sink ships."